In northeastern Nigeria, authorities are struggling with a deadly insurgency that has claimed hundreds of lives in the past month. The government blames the violence on heavily armed suspected Islamist militants, who appear able to strike at will. Critics are calling for President Goodluck Jonathan to do much more to protect civilians in hard-hit areas of the north.

We spoke earlier to NPR's Ofeibea Quist-Arcton. And a warning: This conversation does contain graphic and violent descriptions. It may not be appropriate for children.

OFEIBEA QUIST-ARCTON, BYLINE: Since the weekend, Linda, more than 130 people killed on three consecutive nights of violence. These militants travel in convoy, in pickup trucks; they are heavily armed with assault rifles, rocket-propelled grenades and explosives. And they have been able to strike, killing even more people. So you see an increasingly determined and successful insurgency that has intensified its campaign against the government. But it's not just hitting government targets; it is targeting defenseless civilians in urban areas and in remote villages and of course ,over the past week, children in their beds at a boarding school in a remote area, and then children in Maiduguri - this regional capital - who were celebrating at a wedding party.

WERTHEIMER: Who are these people? What is the ideology of this insurgent group? Are they related to the group Boko Haram, that the government is holding responsible, or is it more than one group here?

QUIST-ARCTON: Boko Haram is the name that generally, the authorities, the military and civilians are giving to this group, although they haven't acknowledged responsibility for all of them. But at the school in Buni Yadi, boys had their throats slit; or they were shot dead or were burned alive in their locked dormitories. Girls were told to give up Western education, go home and get married; and that is one of the keys. Boko Haram has said that it wants to impose strict Islamic law - sharia - on this northeastern region, which is under emergency rule and has been for over a year. But it seems that the military, despite vowing and pledging a crackdown, is simply not able to counter and crush the insurgency.

WERTHEIMER: Now, the U.S. has offered to help Nigeria contain the terrorist battle, as the president and military call it, in Nigeria. Is there concern that this could spill over into some kind of regional conflict?

QUIST-ARCTON: Well, it's already spilling over Nigeria's borders into Cameroon and other parts and, of course, civilians and residents in the rural areas taking refuge. So you have regional governors and politicians in the northeast saying really, the government is talking about rampaging terrorists and that they're going to eliminate them, but they must do much more. And of course, regional governments are worried because we see across the Sahel, this band all the way from Mauritania in the far northwest to Somalia in the Horn of Africa; these Islamist groups able to attack and pillage and kill civilians.

Nigerians are now very worried. Not just Nigerians in the north - Nigerians in the south, they say the government must tackle this properly, and give the army what it needs to stop the bloodshed.